Protractor.



E. D. MORBTON.

PROTRAOTOR. APPLICATION FILED APR. 18, 1914.

Patented Aug. 18,1914.

THE NORRIS PErERs co.. PHOTD-LITHO.. WASHINGTON. D. C.

' blade in angularly adjusted position with I EVERETT D. MORETON, 0F ERIE, PENNSYLVANIA.

PROTRACTOR.

" Specification. of Letters Patent.

Patented Aug. 18, 1914.

Application filed April 18, 1914. Serial No. 832,788.

To all whom/it may concern: I

Be it known that I, EvEREa'r D. MoRn'roN,

a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented new and useful Improvements in Protractors, of which the following is a specification.

This invention relates to drafting instruments and in particular to'limb protractors of the type wherein each instrument includes a flat body .of sheet material havin a semicircular recess, and a movable bla e having a flat head pivotally mounted within thebody recess, the blade and body being constructed so that their adjacent broad faces are absolutely flush. I

The primary object is to provide a secur ing device foruse in locking the movable relation to' the-body, which device is constructed and mounted within the instrument in such a manner that it will be highly efiicient in use butwill not at any point project 7 past blade. The instrument may thus be used either side up and -the body thereof is con- I structed with its base edges at right angles position in dotted lines;

to each other, thereby making it particularly convenient for use in dividing circles, traversing angles, drawing oblique lines at right angles to each other, laying off given angles on each side of a line without changing the setting, and in various other capacitie which should be apparent to persons skilled in theuseof such aninstrument.

The invention consistsin the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawings, which: v

' Figure 1 is a top plan view of the device, the cam lever being shown in its operative position in full lines and in its inoperative 2 is a sectional view on line 2'-2 of Fig. l; and Fig. 3 is a detail perspective view of the locking member.

In the drawing, the numeral 1 designates the flat body of the protractor which is constructed of sheet material and is provided with a circular recess '2 in which the fiat head 3 of the movable blade a is mounted in theusual manner, the head 3 being provlded with a marginal scale 5 of angular measurethe broad, faces of the body or lever is in its op ment and upon the body contiguous thereto with a Vernier 6 reading to five minutes. The body 1 is provided as usual with recesses 7 of considerable area adjacent to the cor ners thereof, whereby the weight of the material is reduced, andthe head 3 of the blade 1 is likewise cut away, one of the head recesses 8 beingcoextensive with the scale and the adjacent edges of the head and body recesses being out concentric to the axis of the blade pivot.

The head of the blade is provided with a circumferential slot 9 opening through its outer edge and being in communication with the recess 8, and the body is provided with'a radially disposedopening 10 in that portion of the body which intervenes between the large recess 2 and th'e medially disposed one of the'recesses 7. to aline with th slot 9 of the blade head. The fiat shank of a lockin member 11 is adapted to extend through t e said opening and slot. The inner end of this member is broadened to provide a head 12 equal in thicknessto the blade head and affording shoulders 13 for engagement with the concave wall of the said recessS. The oppo- This opening is adapted site end of the locking member projects into the medially disposed body slot 7 where it isembraced by the bifurcated portions 14 of the active end of a cam lever 15, which is pivotally connected to the said end of the locking member by means of the pivot pin 16. The lever 15 is provided upon the bifurcated portions of its active end with beveled cam faces 17 for engagement with the correspondingly beveled edge faces 18 of the body recess,whereby tension will be placed upon the locking member, when the cam erative position in'prolongation of the said member, as shown in full lines in Fig. 1, to lock the head 3 of the movable blade in adjusted position within the receiving body recess. The said blade head may thereforebe mounted loosely within the recess'so that it may be operated therein with little friction. When the cam lever is moved into the dotted line position in Fig. 1, it will be inoperative and the movable blade will be released topermit the desired adjustment thereof. The said lever also is cess,

the upper and lower faces of the body, thus to the body and having a circular head roenabling the instrument to lie fiat upon eitherct' its faces.

What is claimed is:

1. In a protractor of the class described, the combination of a flat body having a circular recess its edges, a movable blade equal in thickness to the body and having a circular head rotatably mounted within the circular recess, the blade head being provided with a recess and with an arcuate slot communicating with the said recess and opening through the outer periphery of the head, the said body being provided with a second recess adjacent to the circular recess and with an opening leading radially from the circular recess into the second recess, the said opening being adapted to register with the slot of the blade head, a locking member extending through the said slot and opening and having a head disposed within the recess of the blade head, the outer end of the locking member being extended into the second reand a cam lever pivotally mounted upon the outer end of the locking member and having a cam face for engagement with the inner edge of the said second recess.

2. In L Protractor of theclass described, the combination of a flat body having a circular recess therein opening through one of its edges, a movable blade equal in thickness to the body and havinga circular head rotatably mounted within the circular recess, the blade head being provided with a recess and with an arcuate slot communir eating with the said recess and opening through the outer periphery of the head, the said body being provided with a second recess adjacent to the circular recess and with an opening leading radially from the circular recess into the second recess, the said opening being adapted to register with the slot oi the blade head, a locking member extending through the said slot and opening and having a head disposed within the recess of'the blade head, the outerend of the lOClilllg member being extended into the second recess, and a cam lever pivotally mounted upon the outer end ofthe locking member and having a cam face ment with the inner edge of the said second recess, the outer faces of the locking member head and the cam lever being flush with the corresponding faces of the body and movable blade head. i f

3. In a motractor of the class described, the combination of a flat body having a circular recess therein opening through one of its edges, a movable blade equal in thickness r Goptes of this patent may be obtained for five cents each, by ad therein opening through one of for on on etatably mounted within the circular recess, the blade head being provided with a recess and with an ar-cuate slot communicating with the said recess and opening through the outer periphery of the head, the said body being provided with a second recess adjacent to the circular recess and with an open ing leading radially from the circular recess into the second recess, the said opening being adapted to register with the slot of the blade head, a locking member extending through the said slot and opening and having a head disposed within the recess of the blade head, the outer end of the locking member being extended into the second re-- cess, and a cam lever provided at one ofits ends with bifurcated portions embracing the outer end of the locking member and pivotally connected thereto, the said end portions of the lever being provided with cam faces for engagement with the inner edge of thesecond recess.

ft. In a protractor of the class described, the combination of a flat body having a circular recess therein opening through one of its edges, a movable blade equal in thickness to the body and having a circular head rotatably mounted within the circular recess, the blade headbeing provided with a recess and with. an arcuate slot communicating with the said. recess and opening through the outer periphery of the head, the said body being provided witha second recess adjacent to the circular recess and with an opening leading radially from the circular recess into. the second recess, thesai d opening being adapted to register with the slot of the blade head, a locking member extend ing through the said slot and opening and having ahead disposed within the recess of the blade head, the outer end of the locking member being extended into the second recess, and a cam lever provided at one of its ends with bifurcated portions embracing the outer end of the locking member and pivotally connectedthereto, the said end portions of the lever being provided with cam faces for engagement with the inner edge of the second recess, the inner edge of the second recess being oppositely beveled adjacent to the said opening and the cam faces of the lever being correspondingly beveled for engagement therewith.

In testimony whereof I afiix in presence of two witnesses.

EVERETT D. MORETON. Witnesses:

HENRY L. DOERING, S. H. Drown.

my signature dressing the Commissioner of Patents,

Washington, D. G. 

